Build: Fix AMD dependencies in curCSS

A leftover `rboxStyle` was left in the wrapper parameters but not in the
dependency array, causing `getStyles` to be undefined in AMD mode.

Since `rboxStyle` is no longer used, it's now removed.

Ref gh-4347
Closes gh-4380

src/css/curCSS.js

@@ -2,7 +2,7 @@ define( [
 	"../core",
 	"../core/isAttached",
 	"./var/getStyles"
-], function( jQuery, isAttached, rboxStyle, getStyles ) {
+], function( jQuery, isAttached, getStyles ) {
 
 "use strict";
 

src/css/var/rboxStyle.js

@@ -1,7 +0,0 @@
-define( [
-	"./cssExpand"
-], function( cssExpand ) {
-	"use strict";
-
-	return new RegExp( cssExpand.join( "|" ), "i" );
-} );